Ask J.J. Abrams for his favorite moments from his wildly clever, wildly uneven, superspy drama Alias — returning to ABC’s schedule on April 19 at 8 p.m. to finish off its fifth and final season — and the exec producer gushes geekily. The moment when secret agent Sydney Bristow (Jennifer Garner) seduces intel out of a naughty Russian aboard a plane, then parachutes to safety while the bad guy gets sucked into the engine. The moment when the person torturing Sydney to reveal the location of the Horizon is revealed to be her own mother (played expertly by Lena Olin). And, obviously, the moment when a carton of coffee ice cream prompts Sydney to realize her roommate has been murdered and replaced by a genetically rejiggered doppelgänger. (Francie. Doesn’t. Like. Coffee. Ice cream.)

Yes, Abrams is Alias’ biggest fan — and its most sober critic. Launched in 2001, the sexy-cool spy/sci-fi/family-drama hybrid seemed poised to follow The X-Files as TV’s next great cult sensation. Yet the show never attained great ratings success, despite frequent tinkering designed to make it more accessible — like season 2’s premise-imploding takedown of SD-6, which became necessary because the show ”had become incredibly confusing,” says the producer. Nonetheless, tweaking only seemed to dilute Alias, not unlock its potential. ”The show was always trying to find the balance between what it was and what the powers that be wanted it to be,” says Abrams, whose fertile mind also hatched Felicity and Lost . ”Despite a premise that seemed to have mass appeal, Alias was probably not a mainstream show.” Among the producers’ few regrets, here are the three biggest:

1. DITCHING THE CLIFF-HANGERS Originally, Alias concluded nearly every episode with Sydney in some kind of gasping, to-be-continued peril. But the endings were ditched after season 1 at ABC’s request because they made the episodes too difficult to repeat and sell into syndication. Abrams notes that this was the only instance of pure corporate meddling, and praises the network for allowing his writers to reinstate the device for Alias’ stretch run.

2. REVVING UP THE RAMBALDI According to exec producer Jeff Pinkner, Alias went ”off the rails” when it delved too deeply into its mythology about the mysterious inventions of a 15th-century Italian egghead named Rambaldi. Pointing to season 3, Pinkner says, ” Alias was never designed to be about its mythology, but about its characters.” Abrams agrees: He saw the show as a (dysfunctional) family drama set in a hyperreal world. His ideal Alias includes seasons 1, 2, and 5, plus season 3’s Ricky Gervais and David Cronenberg episodes. ”I’m proud of seasons 3 and 4, but they do have an inherent sense of compromise, as if they were made from the outside looking in.”

3. MISMANAGING SYD’S MEN During Alias’ first season, the writing staff was perplexed by the audience’s ambivalence toward Syd’s friend Will (Bradley Cooper), a reporter whose investigation into the murder of Syd’s fiancé threatened to expose her secret-agent cover. ”We finally realized that the audience didn’t like Will because he was putting Syd at risk. When we were able to do something about it, it was too little, too late,” says Pinkner. Will lasted only two seasons, and ironically is now beloved by fans. More problematic was the dark, vengeance-obsessed turn taken by spy stud Vaughn (Michael Vartan) in season 3 following the wicked betrayal by Lauren, his treacherous double-agent wife. Says Pinkner: ”We could have handled that story line better.”